DE MOIVRE, A(1667-1754)

Improtant among those contributing to probability theory was Abraham De Moivre(1667-1754), a French hugenot who moved to the more congenial political climate of London after the revocation of the Edict of Nantes in 1685. He earned his living in England by private tutoring, and he became an intimate friend of isaac Newton.
De Moivre is particularly noted for his work Annuities upon Lives, which played an important role

in the history of actuarial mathematics, his Doctrine of Chances, which contained much new material on the theory of probability, and his Miscellanea analytica, which contributed to recurrent series, probability, and analytic trigonometry. De Moivre is credited with the first treatment of the probability integral, and of(essentially) the normal frequency curve so important in the study of statistics. The misnamed Stirling's formula, which says that for very large n is due to De Moivre and is highly useful for apporximating factorals of large numbers. The familiar formula

(cos x + i sin x)ⁿ = cos nx + i sin nx, i = Ёю-1,
known by De Moivre's name and found in every theory of equations textbook was familiar to De Moivre for the case where n is a positive integer. This formula has become the keystone of analytic trigonometry. An interesting fable is often told of De Moivre's death. According to the story. De Moivre noticed that each day he required a quarter of an hour more sleep than on the preceding day. When this arithmetic progression reached 24 hours, De Moivre passed away.